Methods of utilizing synthetic resin binder compositions

ABSTRACT

A method of bonding porous, absorbent fibrous materials which comprises applying thereto a water-based synthetic resin binder composition having a pH in the range of from about 2 to about 6 and comprising from about 0.1% to about 60% by weight of a synthetic resin; from about 0.1% to about 6% by weight of a water-soluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight of a water-soluble, polymeric, polyhydroxy compound which does not contain interfering acidic chemical groups; substantially immediately diluting the synthetic resin binder composition whereby a zirconium or aluminum cation is released from the water-soluble salt to substantially immediately destroy the stability of the synthetic resin binder composition and to coagulate the resin with a minimum of further migration and bond the porous, absorbent fibrous materials; and drying the porous, absorbent fibrous materials. The invention also relates to the resulting bonded, porous, absorbent fibrous materials.

United States Patent [1 1 Drelich et al.

[ Dec. 31, 1974 1 1 METHODS OF UTILIZING SYNTHETIC RESIN BINDER COMPOSITIONS [75] Inventors: Arthur H. Drelich, Plainfield; Bobby R. Bowman, East Brunswick, both of NJ.

[73] Assignee: Johnson & Johnson, New

Brunswick, NJ.

22 Filed: Dec.6, 1971 21 Appl. No.: 205,376

[52] US. Cl ..l17/62.2,117/140 A, 117/145, 117/161 C, 117/161 KP, 117/161 UZ, 117/161 P, 117/161 L, 117/161 LN [51] Int. Cl C08k l/02, B44d 1/44 [58] Field of Search. 117/62.2, ll, 58, 76, 138.8 B, 117/140 A,145,161C,161UZ,161KP, 161 P, 161 L, 161 LN Primary Examiner-William D. Martin Assistant Examiner-Janyce A. Bell [5 7 ABSTRACT A method of bonding porous, absorbent fibrous materials which comprises applying thereto a water-based synthetic resin binder composition having a pH in the range of from about 2 to about 6 and comprising from about 0.1% to about 60% by weight of a synthetic resin; from about 0.1% to about 6% by weight of a water'soluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight of a watersoluble, polymeric, polyhydroxy compound which does not contain interfering acidic chemical groups; substantially immediately diluting the synthetic resin binder composition whereby a zirconium or aluminum cation is released from the water-soluble salt to substantially immediately destroy the stability of the synthetic resin binder composition and to coagulate the resin with a minimum of further migration and bond the porous, absorbent fibrous materials; and drying the porous, absorbent fibrous materials. The invention also relates to the resulting bonded, porous, absorbent fibrous materials.

19 Claims, No Drawings METHODS OF UTILIZING SYNTHETIC RESIN BINDER COMPOSITIONS The present invention relates to: water-based synthetic resin binder compositions for bonding porous, absorbent fibrous materials; methods of depositing said synthetic resin binder compositions on porous, absorbent fibrous materials; and the bonded, porous, absorbent, fibrous materials resulting from such bonding methods.

More particularly, the present invention is concerned with the s-called bonded nonwoven textile fabrics, i.e., fabrics produced from textile fibers without the use of conventional spinning, weaving, knitting, or felting operations. Although not limited thereto, the invention is of primary importance in connection with nonwoven fabrics derived from oriented or carded fibrous webs composed of textile-length fibers, the major proportion of which are oriented predominantly in one direction.

Typical of such fabrics are the so-called MAS- SLINN nonwoven fabrics, some of which are described in greater particularlity in US. Pat. Nos. 2,705,687 and 2,705,688, issued Apr. 5, 1955, to D. R. Petterson et a1. and I. S. Ness et al., respectively.

Another aspect of the present invention is its application to nonwoven fabrics wherein the textile-length fibers were originally predominantly oriented in one direction but have been reorganized and rearranged in predetermined designs and patterns of fabric openings or apertures and fiber bundles. Typical of such latter fabrics are the socalled KEYBAK" bundled nonwoven fabrics, some of which are described in particularity in U.S. Pat. Nos. 2,862,251 and 3,033,721, issued Dec. 2, 1958 and May 8, 1962, respectively, to F. Kalwaites.

Still another aspect of the present invention is its application to nonwoven fabrics wherein the textilelength fibers are disposed at random by air-laying techniques and are not predominantly oriented in any one direction. Typical nonwoven fabrics made by such procedures are termed isotropic" nonwoven fabrics and are described, for example, in U.S. Pat. Nos. 2,676,363 and 2,676,364, issued Apr. 27, 1954, to C. H. Plummer et al.

And, still another aspect of the present invention is its application to nonwoven and related fabrics which comprise textile-length fibers and which are made basically by conventional or modified aqueous papermaking techniques such as are described in greater particularity in pending patent application Ser. No. 4,405, filed Jan. 20. 1970 by P. R. Glor and A. H. Drelich. Such fabrics are also basically isotropic and generally have like propeties in all directions.

The conventional base starting material for the majority of these nonwoven and related fabrics is usually a fibrous web comprising any of the common textilelength fibers, of mixtures thereof, the fibers varying in average length from approximately one-half inch to about two and one-half inches. Exemplary of such fibers are the natural fibers, notably cotton, and the synthetic or man-made cellulosic fibers, notably rayon or regenerated cellulose.

Other textile length fibers ofa synthetic or man-made origin may be used in various proportions to replace either partially or perhaps even entirely the previouslynamed fibers. Such other fibers include: polyamide fibers such as nylon 6, nylon 66, nylon 610, etc.; polyester fibers such as Dacron, Fortrel" and Kodel;

acrylic fibers such as Acrilan, Orlon and Creslan; modacrylic fibers such as Verel and Dynel; polyolefinic fibers derived from polyethylene and polypropylene; cellulose ester fibers such as Estron, Arnel and Acele; polyvinyl alcohol fibers; etc.

These textile length fibers may be replaced either partially or entirely by fibers having an average length of less than about one-half inch and down to about onequarter inch. These fibers, or mixtures thereof, are customarily processed through any suitable textile machinery (e.g., a conventional cotton card, a Rando- Webber, a papermaking machine, or other fibrous web producing apparatus) to form a web or sheet of loosely associated fibers, weighing from about grains to about 2,000 grains per square yard or even higher.

If desired, even shorter fibers, such as wood pulp fibers or cotton linters, may be used in varying propor tions, even up to 100% where such shorter length fibers can be handled and processed by available apparatus. Such shorter fibers have lengths less than one-fourth inch.

The resulting fibrous web or sheet, regardless of its method of production, is then subjected to at least one of several types of bonding operations to anchor the individual fibers together to form a self-sustaining web. One method is to impregnate the fibrous web over its entire surface area with various well-known bonding agents, such as natural or synthetic resins. Such over-all impregnation produces a nonwoven fabric of good longitudinal and cross strength, acceptable durability and washability, and satisfactory abrasion resistance. However, the nonwoven fabric tends to be somewhat stiff and boardlike, possessing more of the properties and characteristics of paper or board than those of a woven or knitted textile fabric. Consequently, although such over-all impregnated nonwoven fabrics are satisfactory for many uses, they are still basically unsatisfactory as general purpose textile fabrics.

Another well-known bonding method is to print the fibrous webs with intermittent or continuous straight or wavy lines, or areas of binder extending generally transversely or diagonally across the web and additionally, if desired, along the fibrous web. The resulting nonwoven fabric, as exemplified by a product disclosed in the Goldman U.S. Pat. No. 2,039,312 and sold under the trademark MASSL1NN, is far more satisfactory as a textile fabric than over-all impregnated webs in that the softness, drape and hand of the resulting nonwoven fabric more nearly approach those of a woven or knitted textile fabric.

The printing of the resin binder on these nonwoven webs is usually in the form of relatively narrow lines, or elongated rectangular, triangular or square areas, or annular, circular, or elliptical binder areas which are spaced apart a predetermined distance which, at its maximum, is preferably slightly less than the average fiber length of the fibers constituting the web. This is based on the theory that the individual fibersof the fibrous web should be bound together in as few places as possible.

The nominal surface coverage of such binder lines or areas will vary widely depending upon the precise properties and characteristics of softness, drape, hand and strength which are desired in the final bonded product. In practice, the nominal surface coverage can be designed so that it falls within the range of from about to about 50% of the total surface of the final product. Within the more commercial aspects of the present invention, however, nominal surface coverages of from about 12% to about 40% are preferable.

Such bonding increases the strength ofthe nonwoven fabric and retains substantially complete freedom of movement for the individual fibers whereby the desirable softness, drape and hand are obtained. This spacing of the binder lines and areas has been accepted by the industry and it has been'deemed necessarily so, if the stiff and board-like appearance, drape and hand of the over-ll impregnated nonwoven fabrics are to be avoided.

The nonwoven fabrics bonded with such line and area binder patterns have had the desired softness, drape and hand and have not been undesirably stiff or board-like. However, such nonwoven fabrics have also possessed some disadvantages.

' For example, the relatively narrow binder lines and relatively small binder areas of the applicator (usually an engraved print roll) which are laid down on the fibrous web possess specified physical dimensions and inter-spatial relationships as they are initially laid down. Unfortunately, after the binder is laid down on the web fibrous web and before it hardens or becomes fixed in position, it tends to spread, diffuse or migrate whereby its physical dimensions are increased and its inter-spatial relationships decreased. And, at the same time, the binder concentration in the binder area is lowered and rendered less uniform by the migration of the binder into adjacent fibrous areas. One of the results of such migration is to make the surface coverage of the binder-areas increase whereby-the effect.of the intermittent bonding approaches the effect of the overall bonding. As a result, some of the desired softness, drape and hand are lost and some of the undesired properties of harshness, stiffness and boardiness are increased.

Various methods have been proposed to prevent or to at least limit such spreading, diffusing or migration tendencies of such intermittent binder techniques.

For example, U.S. Pat. No. 3,009,822, issued Nov. 21, 1961 to A. H. Drelich et al., discloses the use of a non-migratory regenerated cellulose viscose binder which is applied in intermittent fashion to fibrous webs under conditions wherein migration is low and the concentration of the binder in the binder area is as high as 35% by weight, based on the weight of the fibers in these binder areas. Such viscose binder possesses inherently reduced spreading, diffusing and migrating tendencies, thereby increasing the desired softness, drape and hand of the resulting nonwoven fabric. This viscose binder has found acceptance in the industry but the use of other more versatile binders has always been sought.

Resins, or polymers as they are often referred to herein as interchangeable terms, are high molecular weight organic compounds and, as used herein, are of a synthetic or man-made origin. These synthetic or man-made polymers have a chemical structure which usually can be represented by a regularly repeating small unit, referred as a mer", andare formed usually either by an addition or a condensation polymerization of one or more monomers. Examples of addition polymers are the polyvinyl chlorides, the polyvinyl acetates, the polyacrylic resins, the polyolefins, the synthetic rubbers, etc. Examples of condensation polymers are the polyurethanes, the polyamides, the polyesters, etc.

Of all the various techniques employed in carrying out polymerization reactions, emulsion polymerization is one of the most commonly used. Emulsion polymerized resins, notably polyvinyl chlorides, polyvinyl acetates, and polyacrylic resins, are widely used throughout many industries. Such resins are generally produced by emulsifying the monomers, stabilizing the monomer emulsion by the use of various surfactant systems, and then polymerizing the monomers in the emulsified state to form a stabilized resin polymer. The resin polymer is usually dispersed in an aqueous medium as discrete particles of colloidal dimensions (1 to 2 microns diameter or smaller) and is generally termed throughout the industry as a resin dispersion". or a resin emulsion or latex".

Generally, however, the average particle size in the resin dispersion is in the range of about 0.l micron (or micrometer) diameter, with individual particles ranging up to l or 2 microns in diameter and occasionally up to as high as about 3 or 5 microns in size. The particle sizes of such colloidal resin dispersions vary a great deal, not only from one resin dispersion to another but even within one resin dispersion itself.

The amount of resin binder solids in the resin colloidal aqueous dispersion varies from about 0.1% solids by weight up to about by weight or even higher solids, generally dependent upon the nature of the monomers used, the nature of the resulting polymer resin, the surfactant system employed, and the conditions under which the polymerization was carried out.

These resin colloidal dispersions, or resin emulsions, or latexes, may be anionic, non-ionic, or even polyionic and stable dispersions are available commercially at pHs of from about 2 to about 10.5.

However, in order to realize the advantages and benefits ofthe present invention, the synthetic resin dispersions are employed herein in an acidic pH range of from about 2 to about 6. As a consequence, those resin emulsions which are commercially available with a pH greater than about 6 must be acidified first with an acid, such as acetic acid, so that they come within the desired pH range. This naturally leads to another requirement of the resin dispersions, namely, that they must be stable at a pH range of from about 2 to about 6. Within the preferred commercial uses of this invention, a pH range of from about 3 to about 5 is found more desirable.

The amount of resin which is applied to the porous or absorbent material varies within relatively wide limits, depending upon the resin itself, the nature and character of the porous or absorbent materials to which the resins are being applied, its intended use, etc. A general range of from about 3% by weight up to about by weight, based on the weight of the porous or absorbent material, is satisfactory under substantially all uses. Within the more commercial limits, however, a range of from about 10% to about 50% by weight, based on the weight of the porous or absorbent material, is preferred.

Such resins have found use in the coating industries for the coating of woven fabrics, paper and other materials. The resins are also used as adhesives for laminating materials or for bonding fibrous webs. These resins have also found wide use as additives in the manufacture of paper, the printing industry, the decorative printing of textiles, and in other industries.

In most instances, the resin is colloidally dispersed in water and, when applied from the aqueous medium to a porous or absorbent sheet material which contains additional water is carried by the water until the water is evaporated or otherwise driven off. If it is desired to place the resin only on the surface of the wet porous or absorbent sheet material and not to have the resin penetrate into the porous or absorbent sheet material, such is usually not possible inasmuch as diffusion takes place between the aqueous colloidal resin and the water in the porous material. In this way, the colloidal resin tends to spread into and throughout the porous material and does not remain merely on its surface.

Of, if it is desired to deposit the aqueous colloidal resin in a specific intermittent print pattern, such is used in bonding nonwoven fabrics, the aqueous colloidal resin tends to diffuse and to wick along the individual fibers and to carry the resin with it beyond the confines of the nominal intermittent print pattern. As a result, although initially placed on the nonwoven fabric in a specific intermittent print pattern, the ultimate pattern goes far beyond that due to the spreading or migration which takes place due to the diffusion of the water and the resin, until the water is evaporated or otherwise driven off.

We have discovered new resin binder compositions containing polymers colloidally dispersed in aqueous acidic media and new methods of applying such resin binder compositions to porous or absorbent fibrous materials, whereby the resins are applied in a controlled, relatively non-migrating manner. If it is desired that the resin be placed only on the surface of the porous or absorbent material, our compositions and methods will allow this to be done. Furthermore, if it is desired that the resin be impregnated throughout the material, from one surface to the other surface, again, our composition and method will allow this to be done.

We have now discovered an improved method of controllably depositing acidic colloidal resin composi tions on porous or absorbent materials whereby spreading, diffusing, and migration of the resin are controlled and are markedly reduced.

The improved method involves the use of a waterbased synthetic resin emulsion or dispersion which comprises from about 0.1% to about 60% (and preferably from about to about 50%) by weight on a solids basis of a colloidally dispersed synthetic resin; from about 0.1% to about 6% (and preferably from about 0.5% to about 4%) by weight, based on the weight of the synthetic resin, of a water-soluble salt of zirconium or aluminum and, from about 0.05% to about 3% (and preferably from about 0.1% to about 2%) by weight, based on the weight of the synthetic resin, of a water-soluble polymeric polyhydroxy compound which does not contain interfering acidic chemical groups, of which the carboxylic group is a notable example. The remainder of the aqueous emulsion or dispersion is water which is in the range of from about 35% to about 65% by weight of the total emulsion or dispersion.

The synthetic resin may be selected from a relatively large group of synthetic resins well known in industry for bonding purposes. Specific examples of such synthetic resins include: polymers and copolymers of vinyl chloride such as plasticized and unplasticized polyvinyl chloride, polyvinyl chloride-polyvinyl acetate, ethylene-vinyl chloride, etc.; polymers and copolymers of vinyl acetate such as plasticized and unplasticized polyvinyl acetate, ethylene-vinyl acetate, etc.; the polyacrylic resins such as ethyl acrylate, methyl acrylate, butyl acrylate, ethyl-butyl acrylate, ethyl hexyl acrylate, hydroxyethyl acrylate, dimethyl amino ethyl acrylate, etc.; the polymethacrylic resins such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate; polyvinyl alcohol-acrylic copolymers; the polyolefinic resins, including ethylenevinyl chloride and ethylene-vinyl acetate which have been listed previously; the synthetic rubbers such as butadiene-acrylonitrile, butadiene-styrene, chlorinated rubber, etc., natural latex; the polyurethanes; the polyamides; the polyesters; the aldehyde resins, such as urea formaldehyde, melamine formaldehyde, phenol formaldehyde, resorcinol formaldehyde. etc.

These resins may be used either as homopolymers comprising a single repeating monomer unit, or they may be used as copolymers comprising two, three; or more different monomer units which are arranged in random fashion, or in a definite ordered alternating fashion, within the polymer chain. Also included within the inventive concept are the block polymers comprising relatively long blocks ofdifferent monomer units in a polymer chain and graft polymers comprising chains of one monomer attached to the backbone of another polymer chain. It is therefore to be noted that the invention is applicable to substantially any resin which is available in a latex or dispersion form.

As pointed out previously, the compositions and formulations containing these polymers or copolymers must be stable at a pH range of from about 2 to about 6 which is the range wherein they are utilized, with preferred ranges extending from about 3 to about 5. Such stability is particularly required for these polymer dispersions, when existing at their normal concentration levels in the presence of water-soluble salts of zirconium and/or aluminum.

The water-soluble salt of zirconium or aluminum which is included in the water-based resin binder com position is selected, of c0urse,'from a much smaller group. Examples of such water soluble salts are zirconium acetate, zirconium sulfate, zirconium nitrate, aluminum basic diacetate, aluminum sulfate, aluminum chromium sulfate, aluminum potassium sulfate. aluminum ammonium sulfate, aluminum nitrate, aluminum bromate, aluminum bormide, aluminum chlorate, etc. These water-soluble salts may be used individually or collectively in a mixture.

The watersoluble polymeric polyhydroxy compound may be selected from a relatively large group of such compounds containing at least two hydroxy groups or more per molecule, but it is necessary that such watersoluble polymeric polyhydroxy compounds do not contain substituent chemical groups which would interfere with the functioning ofthe polyhydroxy compound. Examples of such interfering chemical groups are the acidic groups to be defined in greater detail hereinafter.

Specific examples of water-soluble polymeric polyhydroxy compounds which are suitable for use in the application ofthe present inventive concept are: hydroxymethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, ethyl cellulose, methyl cellulose, poly vinyl alcohol, polyethylene glycol, carbohydrates such as starch and starch derivatives including hydrolyzed starch, oxidized starch, soluble starch, etc.

With reference to the term polymeric" as used herein, this term covers chemical compounds wherein relatively small chemical units normally called monomers react with each other to create relatively large molecules normally called polymers. With the exception of the two terminal monomeric units, all the internal monomeric units in the basic polymer chain are normally essentially identical, or are basically interrelated, such as occurs when two or more different monomers are polymerized together to form a copolymer, rather than a homopolymer when only one monomer is used. The molecular weight of such polymers varies widely but, for the purposes of the present invention, is at least about 400 and is preferably higher. Those polymers having molecular weights about 400 or moderately above that value are frequently referred to as oligomers" showing at least about 8 repetitive monomeric units as a minimum.

It is again to beappreciated that such watersoluble polyhydroxy compounds must be stable at their operational pH range of from about 2 to about 6 and preferably from about 3 to about 5, particularly when they are in the presence of water soluble salts of zirconium and aluminum.

It is also to be noted that these water-soluble polyhydroxy compounds do not contain any interfering acidic chemical groups which are likely to react with these water-soluble salts when they exist together in a stable resin dispersion at its normal levels of concentration and at a pH range of from about 2 to about 6. As defined herein, examples of such acidic chemical groups" include such groups as carboxy (COOH), sulfino (SOOH), sulfo (SO OH), sulfonoamino (NHSO- H), aci-nitro (NOOH), hydroxyamino (NHOH), hydroxyimino (NOH), or other acid or like groups which are capable of reacting with water soluble zirconium and aluminum salts at a pH between about 2 and about 6 in the formulated synthetic resin dispersion to prematurely coagulate and break the synthetic resin dispersion and thereby prevent the subsequent desired reaction.

The synthetic resin, the water-soluble salts of zirconium or aluminum, and the water soluble polymeric polyhydroxy compound exist together in a stable, acidic, water-based emulsion or dispersion form at a pH in the range of from about 2 to about 6 and normally do not agglomerate, coagulate, or precipitate as long as their stable concentration levels or degrees of dilution are maintained.

However, if the emulsion or dispersion is diluted with water or other aqueous media to a sufficiently low degree, the synthetic resin substantially immediately coagulates and agglomerates in place wherever deposited with substantially no further spreading, diffusion or migration.

It is believed, although not predicted by chemical theory, that when the resin emulsion or dispersion is diluted sufficiently, the zirconium or aluminum metal cation is in some inexplicable manner released from the water soluble salt, or becomes chemically more active, and immediately attacks or reacts with the water solu ble polymeric polyhydroxy compound, destroying the stability of the resin emulsion or dispersion, and causing the resin particles to agglomerate or coagulate in place very rapidly.

The dilution with water or other aqueous medium may be effected in different ways in order to activate the reaction mechanism. For example, the porous, ab-

sorbent fibrous materials may be pre-treated by being pre-wetted with a sufficient quantity of an aqueous medium, preferably water, whereby the colloidal resin composition substantially immediately becomes sufficiently diluted upon contact therewith. Or, if desired, the colloidal resin composition may be first printed on the porous, absorbent fibrous materials and then subsequently treated with the aqueous medium such as wa' ter, to effect the dilution whereupon the colloidal resin particles substantially immediately agglomerate or coagulate in place with substantially no further spreading, diffusion, or migration.

The amount of the water applied to the porous, absorbent fibrous materials varies relatively widely. depending upon many factors, the most important of which is the nature, concentration, and the physical and chemical properties and characteristics of l) the synthetic resin, (2) the specific water soluble salt of zir' conium or aluminum, and (3) the specific water solublc polymeric polyhydroxy compound.

Normally, the amount of water applied to the fibrous material brings its water content into the range of from about to about 300% by weight and preferably from about to about 250%, based on the weight of the fibrous materials being treated. Such amounts of water are controlled and adjusted by means of suitable conventional vacuum stripping apparatus, nip-rolls, squeeze-rolls, etc.

The amount of water which is applied to the fibrous materials also affects the degree of control exercized over the coagulation and migration. The greater the amount of water, the greater is the control and the more rapid is the coagulation and the less is the migration of the binder. On the ohter hand, the less the amount of water in the fibrous materials, then the less is the control which is exercised, the less rapid is the coagulation, and the greater is the migration of the binder.

The invention will be further illustrated and described in the following specific examples. It should be understood, however, that, although these examples may describe in particular detail some of the more specific features of the present invention, they are given primarily for purposes of illustration and the broader aspects of the present inventive concept are not to be construed as limited thereto.

EXAMPLE I A fibrous card web weighing about 591 grains per square yard and comprising 100% rayon fibers 1 /2 denier and l-9/l6 inches in length is rearranged into a pattern of fiber bundles and fabric openings by procedures set forth in the apparatus illustrated in FIG. 7-] l ofU.S. Pat. No. 2,862,251. The particular pattern comprises approximately l65 circular openings (0.045-inch diameter) per square inch in a staggered or nesting pattern. See FIG. 48 of U5. Pat. No. 2,862,25l.

The rearranged fibrous web is treated with water and squeezed to a moisture control of 177%, that is, 177 grams of water per 100 grams of dry fiber.

The rearranged fibrous web is intermittently print bonded with a torpedo print pattern such as illustrated in FIG. 6 of US. Pat. No. 3,009,823. The synthetic resin binder used to bond the web has a pH of 3.5 and comprises the following formulation: ,190

Excellent control is obtained over the application of the print binder and spreading, diffusing and migrating thereof is held to a minimum, as evidenced by visual observations of the pigmented bonded areas in the final product. The bonded fibrous web is dried and cured on steam cans at a temperature of about 310F. The binder areas are clean and sharply defined. The bonded fibrous materials possess excellent hand, drape and softness and excellent strength. The final product is a well bonded, porous, absorbent nonwoven fabric which weighs 980 grains per square yard, thus indicating a binder add-on of 389 grains per square yard, or 66% binder add-on, based on the weight of the fibrous materials. It finds excellent use as a bonded nonwoven fabric wash-cloth.

EXAMPLE II The procedures of Example I are carried out substantially as set forth therein with the exception that the following synthetic resin binder formulation is used:

National Starch NS4260, a non-ionic acrylic resin (W1 solids) pH 3.5 4540 grants Antifoam 45 grams Blue pigment 45 grams Zirconium sulfate (50% solution) ml.

Zirconium acetate (2371 solution) 120 mlv Hydroxyethyl cellulose (2% solution) 480 grams Water 1400 ml.

The results are generally comparable to those obtained in Example I. The migration ofthe binder is held to a minimum. The final product is a well bonded, porous, absorbent nonwoven fabric which has excellent softness, drape, and hand and has excellent strength. It finds excellent use as a shop towel.

EXAMPLE Ill The procedures of Example I are followed substantially as set forth therein except that the following syn thetic resin binder formulation is used:

Goodrich (icon 576 anionic polyvinyl The results are generally comparable to those obtained in Example I. The migration of the binder is held to a minimum. The final nonwoven fabric has excellent softness, drape, and hand and has excellent strength. It finds use as a sports towel.

EXAMPLE IV The procedures of Example I are followed substan tially as set forth therein with the exception that the following synthetic resin binder formulation is used:

National Starch NS2S42 anionic plasticized polyvinyl acetate (SH/1 solids) pH 3.9 2724 grams Antifoam 30 grants Pigment 30 grams Zirconium acetate (23% solution) 50 ml.

Hydroxyethyl cellulose (27: solution) 454 grams Water 1362 grants The results are generally comparable to those obtained in Example I. The migration is held to a minimum. The final product has excellent softness, drape and hand and has excellent strength, It finds use as a wash cloth.

EXAMPLE V The procedures of Example I are followed substantially as set forth therein with the exception that the following synthetic resin binder formulation is used:

DuPont EP l966 NF anionic vinyl acetate-ethylene copolymer (Sti /1 solids) pH 4.3 3000 grants Antifoam 30 grants Pigment 30 grants Zirconium acetate (23% solution) 50 ml.

Hydroxyethyl cellulose (2% solution) 440 grants Water I250 grants The results are generally comparable to those obtained in Example I. The migration ofthe binder is kept to a minimum. The final product is a well bonded porous, absorbent nonwoven fabric which has excellent softness, drape, and hand and has excellent strength.

EXAMPLE VI The procedures of Example I are followed substantially as set forth therein with the exception that the following synthetic resin binder formulation is used:

Air Reduction Aircoflex 510. a colloidally stabilized. nonionic polyethylene-vinyl acetate copolymer (55% solids) pH 5.) 4000 grants Antifoam 30 grants Blue pigment 30 grams Zirconium acetate (23'7: solution) (changes dispersion to pH 4.8) ml. Hydroxyethyl cellulose (27: solution) 400 grams Water I400 ml.

The results are generally comparable to those obtained in Example I. The migration of the binder is minimal. The final product has excellent softness. drape and hand and has excellent strength.

EXAMPLE VII The procedures of Example I are followed substantially as set forth therein with the exception that the following synthetic resin binder formulation is used:

Monsanto RPC1400, a polyethylene-vinyl The results are generally comparable to those obtained in Example I. The migration of the binder is minimal. The final product is a well bonded, porous, absorbent nonwoven fabric which has excellent softness, drape, and hand and has excellent strength.

EXAMPLE VIII The procedures of Example I are followed substantially as set forth therein with the exception that the resin binder formulation is:

Wyandotte X1042, Polyurethane latex (50% solids) pH 7.3 4540 grams Antifoam 30 grams Blue pigment 30 grams Zirconium acetate (23% solution) to pH 5.4 50 ml.

Hydroxyethyl cellulose (2% solution) 400 grams Water grams The results are generally comparable to those obtained in Example I. The migration of the binder is minimal. The resulting bonded nonwoven fabric is porous and absorbent and is soft, drapeable and of good hand. It ossesses good strength and is suitable as a shop towel or wipe.

EXAMPLE IX EXAMPLE X The procedures of Example I are followed substantially as set forth therein with the exception that 8 grams of Dow Ethocel, ethyl cellulose (water soluble grade) is used to replace the 7.8 grams of hydroxyethyl cellulose.

The results are generally comparable to those obtained in Example I. The migration of the binder is minimal. The final product has excellent softness, drape, and hand and hasexcellent strength.

EXAMPLE XI The procedures of Example I are followed substantially as set forth therein with the exception that 9 grams of polyethylene glycol 400 is used to replace the 7.8 grams of hydroxyethyl cellulose.

The results are generally comparable to those obtained in Example I. The migration ofthe binder is minimal. The final product has excellent softness, drape, and hand and has excellent strength.

EXAMPLE XII The procedures of Example I are followed substantially as set forth therein with the exception that 8 grams of water soluble polyvinyl alcohol is used to replace the 7.8' grams of hydroxyethyl cellulose.

The results are generally comparable to those ob tained in Example I. The migration of the binder is minimal. The final product has excellent softness, drape, and hand and has excellent strength.

EXAMPLE XIII The procedures of Example I are followed substantially as set fotth therein with the exception that. 9 grams of cold water soluble starch is used to replace the 7.8 grams of hydroxyethyl cellulose.

The results are generally comparable to those obtained in Example I. The migration of the binder is minimal. The final product has excellent softness, drape, and hand and has excellent strength.

EXAMPLE XIV The procedures of Example I are followed substantially as set forth therein with the exception that 9 grams of hydrolyzed starch is used to replace the 7.8 grams of hydroxyethyl cellulose.

The results are generally comparable to those obtained in Example I. The migration of the binder is minimal. The final product has excellent softness, drape, and hand and has excellent strength.

EXAMPLE XV The procedures of Example I aree followed substantially as set forth therein with the exception that 9 grams of oxidized starch is used to replace the 7.8 grams of hydroxyethyl cellulose.

The results are generally comparable to those obtained in Example I. The migration ofthe binder is minimal. The final product has excellent softness, drape, and hand and hasexcellent strength.

EXAMPLE XVI The procedures of Example I are followed substantially as set forth therein in a series of similar procedures with the exception that the water soluble salt of Example I (zirconium sulfate and zirconium acetate) is replace by:

a. Zirconium nitrate (9 grams); or I b. Aluminum basic diacetate (9 grams); or

c. Aluminum sulfate (10 grams); or

d. Aluminum potassium sulfate (8 grams); or

e. Aluminum ammonium sulfate (10 grams); or

f. Aluminum nitrate (12 grams).

The results in all cases are generally comparable to the results obtained in Example I. Migration-of the binder is minimal. The final product is a well bonded porous, absorbent nonwoven fabric which is soft and drapeable and has good hand and strength.

EXAMPLE XVII and (b) to 240%. The results in both cases are generally comparable to the results obtained in Example I and there is a minimum of spreading, diffusing, and migrating of the applied binder.

Although the present invention has been described in particularity in the present examples by reference to specific materials and formulations, it is to be appreciated that such is merely illustrative of the present invention and is not to be construed as limitative thereof, except as defined by the appended claims.

ln these Examples, the percent concentrations of the solutions or dispersions used are set forth, whereby the true amounts of the various constituents may be calculated on a true solids basis in grams or other units of weight.

We claim:

1. A method of bonding porous, absorbent fibrous materials which comprises applying thereto a waterbased synthetic resin binder composition having a pH in the range offrom about 2 to about 6 and comprising: from about 0.1% to about 60% by weight on a solids basis of a colloidally dispersed synthetic resin; from about 0.1% to about 6% by weight, based on the weight of the colloidally dispersed synthetic resin, of a watersoluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight, based on the weight of the colloidally dispersed synthetic resin, of a watersoluble polymeric polyhydroxy compound which does not contain interfering acidic chemical groups; substantially immediately diluting said synthetic resin binder composition whereby a zirconium or aluminum cation is released from said water-soluble salt to substantially immediately destroy the stability of said synthetic resin binder composition and to coagulate said resin with a minimum of further migration and bond the porous, absorbent fibrous materials; and drying said porous, absorbent fibrous materials.

2. Porous, absorbent, textile fibrous bonded by the method of claim 1.

3. A method of bonding porous, absorbent fibrous materials which comprises applying thereto sufficient water to bring the water content thereof into the range of from about 100% to about 300% by weight, based on the weight of the porous, absorbent fibrous materials, and then applying thereto a waterbased synthetic resin binder composition having a pH in the range of from about 2 to about 6 and comprising: from about 0.1% to about 60% by weight on a solids basis of a colloidally dispersed synthetic resin; from about 0.1% to about 6% by weight, based on the weight of the colloidally dispersed synthetic resin, of a water-soluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight, based on the weight of the colloidally dispersed synthetic resin, of a water-soluble polymeric polyhydroxy compound which does not contain interfering acidic chemicals groups; whereby a zirconium or aluminum cation is released from said water-soluble salt to substantially immediately destroy the stability of said synthetic resin binder composition and to coagulate said resin with a minimum of further migration and bond the porous, absorbent fibrous materials; and drymaterials ing said porous, absorbent fibrous materials.

4. A method of bonding porous, absorbent fibrous materials which comprises applying thereto a waterbased synthetic resin binder composition having a pH in the range of from about 2 to about 6 and comprising:

from about 0.l% to about 60% by weight on a solids basis of a colloidally dispersed synthetic resin; from about 0.1% to about 6% by weight, based on the weight of the colloidally dispersed synthetic resin, of a watersoluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight, based on the weight of the colloidally dispersed synthetic resin, of a watersoluble polymeric polyhydroxy compound which does not contain interfering acidic chemical groups; substantially immediately diluting said synthetic resin binder composition whereby a zirconium or aluminum cation is released from said water-soluble salt to substantially immediately destroy the stability of said synthetic resin binder composition and to coagulate said resin with a minimum of further migration and drying the porous, absorbent fibrous materials to bond the same.

5. A method as defined in claim 1 wherein the colloidal synthetic resin is an acrylic resin.

6. A method as defined in claim 1 wherein the colloidal synthetic resin is polyvinyl chloride.

7. A method as defined in claim 1 wherein the colloidal synthetic resin is polyvinyl acetate.

8. A method as defined in claim 1 wherein the colloidal synthetic resin is a vinyl acetate-ethylene copolymer.

9. A method as defined in claim 1 wherein the colloidal synthetic resin is an ethylene-vinyl chloride copolymer.

10. A method as defined in claim 1 water-soluble salt is zirconium sulfate.

11. A method as defined in claim 1 water-soluble salt is zirconium acetate.

12. A method as defined in claim 1 water-soluble salt is zirconium nitrate.

13. A method as defined in claim 1 water-soluble salt is aluminum sulfate.

14. A method as defined in claim 1 water-soluble salt is aluminum nitrate.

15. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is hydroxethyl cellulose.

16. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is methyl cellulose.

17. A method as defined in'claim 1 wherein the water-soluble polymeric polyhydroxy compound is ethyl cellulose.

18. A method as defined in claim 1 wherein the watersoluble polymeric polyhydroxy compound is polyethylene glycol.

19. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is polyvinyl alcohol.

wherein the wherein the wherein the wherein the wherein the 2- UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 57,7 Dated December 3 97 Inventor) Arthur H. Drelich and Bobby R. Bowman It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 1, line 51, isotropic should read "isotropic" In Column 3, line 12, "over-ll" should read over-all In Column 3, line 25, "web fibrous web" should read wet fibrous web In Column 5,1ine 1h, "0f,if it is" should read Or, if it is In Column 7, line 19, "watersoluble" should read water-soluble In Column 8, line 68, "formulatiom, 190" should read formulation:

In Column 9, line 1, the following chart has been omitted,

Rohm & Haas HA-l6, a non-ionic, relatively firm tel-polymer of methylmethacrylate, ethyl acrylate and N-methylol-acrylamide 16$ solids) 816 grams Rohm & Haas PIA-8, a non-ionic relatively soft terpolymer of methylmethacrylate, ethyl acrylate and N-methylol-acrylamide &8; solids) 216 grams Nopco NXZ silicone antifoam 60 grams DuPont lhl Monastral Blue pigment 20 grams Zirconium sulfate(50$ solution) 10 ml. Zirconium acetate (23% solution) 20 ml. Hercules 250 HR hydroxyethyl cellulose (2% solution) 39 grams Water 1&00 ml.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIGN tent N 57,728 Dated December 51, 197A Inventor) Arthur H. Dr-elich and Bobby R. Bowman Page 2 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 12, line 57, "Example 1 aree" should read Example 1 are Signed and sea led this 27th day of I-iay 1975.

(SEAL) Att St:

8 C. MARSHALL DANN RUTH C. MASON Commissioner of Patents 'Attesting Officer and Trademarks FORM PO-105O (10-69) USCOMM-DC 60376-F'69 U15 GOVERNMENT PRINTING OFFICEi 869. 930 

1. A METHOD OF BONDING POROUS, ABSORBENT FIBROUS MATERIALS WHICH COMPRISES APPLYING THERETO A WATER-BASED SYNTHETIC RESIN BINDER COMPOSITION HAVING A PH IN THE RANGE OF FROM ABOUT 2 TO ABOUT 6 AND COMPRISING: FROM ABOUT 0.1% TO ABOUT 60% BY WEIGHT ON A SOLIDS BASIS OF A COLLOIDALLY DISPERSED SYNTHETIC RESIN; FROM ABOUT 0.1% TO ABOUT 6% BY WEIGHT, BASED ON THE WEIGHT OF THE COLLOIDALLY DISPERSED SYNTHETIC RESIN, OF A WATER-SOLUBLE SALT OF ZIRCONIUM OR ALUMINUM; AND FROM ABOUT 0.05% TO ABOUT 3% BY WEIGHT, BASED ON THE WEIGHT OF THE COLLOIDALLY DISPERSED SYNTHETIC RESIN, OF A WATER-SOLUBLE POLYMERIC POLYHYDROXY COMPOUND WHICH DOES NOT CONTAIN INTERFERING ACIDIC CHEMICAL GROUPS; SUBSTANTIALLY IMMEDIATELY DILUTING SAID SYNTHETIC RESIN BINDER COMPOSITION WHEREBY A ZIRCONIUM OR ALUMINUM CATION IS RELEASED FROM SAID WATER-SOLUBLE SALT TO SUBSTANTIALLY IMMEDIATELY DESTROY THE STABILITY OF SAID SYNTHETIC RESIN BINDER COMPOSITION AND TO COAGULATE SAID RESIN WITH A MINIMUM OF FURTHER MIGRATION AND BOND THE POROUS, ABSORBENT FIBEROUS MATERIALS; AND DRYING SAID POROUS, ABSORBENT FIBROUS MATERIALS.
 2. Porous, absorbent, textile fibrous materials bonded by the method of claim
 1. 3. A method of bonding porous, absorbent fibrous materials which comprises applying thereto sufficient water to bring the water content thereof into the range of from about 100% to about 300% by weight, based on the weight of the porous, absorbent fibrous materials, and then applying thereto a water-based synthetic resin binder composition having a pH in the range of from about 2 to about 6 and comprising: from about 0.1% to about 60% by weight on a solids basis of a colloidally dispersed synthetic resin; from about 0.1% to about 6% by weight, based on the weight of the colloidally dispersed synthetic resin, of a water-soluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight, based on the weight of the colloidally dispersed synthetic resin, of a water-soluble polymeric polyhydroxy compound which does not contain interfering acidic chemicals groups; whereby a zirconium or aluminum cation is released from said water-soluble salt to substantially immediately destroy the stability of said synthetic resin binder composition and to coagulate said resin with a minimum of further migration and bond the porous, absorbent fibrous materials; and drying said porous, absorbent fibrous materials.
 4. A method of bonding porous, absorbent fibrous materials which comprises applying thereto a water-based synthetic resin binder composition having a pH in the range of from about 2 to about 6 and comprising: from about 0.1% to about 60% by weight on a solids basis of a colloidally dispersed synthetic resin; from about 0.1% to about 6% by weight, based on the weight of the collOidally dispersed synthetic resin, of a water-soluble salt of zirconium or aluminum; and from about 0.05% to about 3% by weight, based on the weight of the colloidally dispersed synthetic resin, of a water-soluble polymeric polyhydroxy compound which does not contain interfering acidic chemical groups; substantially immediately diluting said synthetic resin binder composition whereby a zirconium or aluminum cation is released from said water-soluble salt to substantially immediately destroy the stability of said synthetic resin binder composition and to coagulate said resin with a minimum of further migration and drying the porous, absorbent fibrous materials to bond the same.
 5. A method as defined in claim 1 wherein the colloidal synthetic resin is an acrylic resin.
 6. A method as defined in claim 1 wherein the colloidal synthetic resin is polyvinyl chloride.
 7. A method as defined in claim 1 wherein the colloidal synthetic resin is polyvinyl acetate.
 8. A method as defined in claim 1 wherein the colloidal synthetic resin is a vinyl acetate-ethylene copolymer.
 9. A method as defined in claim 1 wherein the colloidal synthetic resin is an ethylene-vinyl chloride copolymer.
 10. A method as defined in claim 1 wherein the water-soluble salt is zirconium sulfate.
 11. A method as defined in claim 1 wherein the water-soluble salt is zirconium acetate.
 12. A method as defined in claim 1 wherein the water-soluble salt is zirconium nitrate.
 13. A method as defined in claim 1 wherein the water-soluble salt is aluminum sulfate.
 14. A method as defined in claim 1 wherein the water-soluble salt is aluminum nitrate.
 15. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is hydroxethyl cellulose.
 16. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is methyl cellulose.
 17. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is ethyl cellulose.
 18. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is polyethylene glycol.
 19. A method as defined in claim 1 wherein the water-soluble polymeric polyhydroxy compound is polyvinyl alcohol. 